There is described a wheelchair (1) comprising a seat portion (5), including a seat structure (50), a foot portion (6), a pair of wheels (3) and a wheelchair frame (2) extending between the seat portion (5) and the foot portion (6). The wheelchair frame (2) comprises a cross-member (27/28) having first and second ends coupled to the wheels (3), first and second side frame members (21, 22) extending on each side of the wheelchair frame (2) from the first end, respectively second end, of the cross-member (27/28) to the foot portion (6), and a central support structure (25/250/500) located on a middle portion of the cross-member (27/28), which central support structure (25/250/500) supports the seat structure (50). The wheelchair frame (2) further comprises a linking structure (23/24) extending from the middle portion of the cross-member (27/28) to each one the first and second side frame members (21, 22), at the foot portion (6). Also described is a wheelchair (1) comprising a height-adjustable seat structure (50).
